Under the Hood: Sonos brings multi-zone digital audio to life

As the world migrates to digital music, how should an audio system look and feel if it were designed from scratch? That was the clean-sheet thinking that drove the engineers at Sonos Inc. Rallying around an emphasis on ease of use, software upgradability, multi-room capability and wireless connectivity and control, their designers' thoughts jelled in the form of the Sonos Digital Music System, a multi-zone digital music system with a wireless, full-color LCD screen controller that lets users play all their digital music, anywhere in their home or yard, while controlling it all from the palm of their hand. No server required.

Historically, audio systems were all about amps and speakers, according to Andrew Schulert, vice president of product development at Sonos. But people weren't buying amps or stereos like they used to," he said, thanks to the rise of digital formats such as MP3. "So the question became, 'How would it be done now?'"

First announced in 2004, the system has gone through no less than eight downloadable upgrades that now not only gives users access to their own local music archives -- a veritable jukebox for the entire home -- but also to Internet radio and music outlets such as Napster, Rhapsody and Sirius.

While the Sonos Digital Music System now quite admirably answers the question of how digital audio should be handled, the designers had to overcome many problems along the way. Those problems included making the system as simple to use as a legacy audio appliance, enabling system upgrades in a rapidly changing consumer space, multi-room audio synchronization and of course ensuring reliable, latency-free wireless connectivity. On top of that, the design team was thrown some curve balls, such as RF harmonic interference and problems derived from designing the motion-sensitive controller separately from the cradle it goes into.

The base system costs $1,000 and comprises two ZonePlayers - the ZP100 and ZP80 - accompanied by a single wireless controller. The ZonePlayers can access and play a wide variety of music formats, including MP3, WMA, AAC (MPEG4) and WAV, stored on a PC, Mac or network attached storage (NAS), and comes bundled with customizable Internet radio stations. Built-in wired and secure wireless capabilities provide the consumer flexibility of installation at no extra cost.

The ZP100 comes with an integrated amplifier that distributes, plays and amplifies music in any "zone" in the home. The device is spec'd to deliver 50 W/channel into 8 Ohms or 120 W/channel into 4 Ohms, with a total harmonic distortion of 0.02 . (Off the record, it can actually deliver a bit more than that, up to 68 W/channel into 8 Ohms). The ZP80 has no amplifier and is instead designed to integrate into an existing audio system or simple off-board amplifier/speaker system. Either device can form the wired connection to the home network, though the ZP100 has a 4-port Ethernet switch compared to the ZP80's 2-port switch. Both have digital (optical and coaxial) and analog RCA inputs and outputs. The wireless controller comes with a rechargeable battery that rests in its own powered cradle when not in use. It has a full-color screen, a powerful touch scroll wheel and it allows the user to access, customize and control any of up to 32 ZonePlayers  anywhere. From the bedroom to the backyard.

The latest addition to the lineup is the ZoneBridge, which simplifies setup of the SonosNet wireless network and extends the range of the network to remote locations, such as a garage or guest house. Its Ethernet jacks also bring Internet connectivity to PVRs, settop boxes etc.. It retails for $99.